The hobbyists 'Quick questions' thread

[Nick]

It feels like every time I have a simple/silly question about pedal (or general) electronics, I'm always hassling the same people for help. Surely there are other newbs like me out there that find themselves in similar predicaments? And maybe by posting our questions in public, we're also doing a favour to our regular helpers by giving them a break?!


I'll get the ball rolling...

I'm troubleshooting an effects unit of mine with a built-in transformer (as opposed to being battery-powered). Are there any extra precautions that I need to take, before measuring the electrolytic capacitors with my LCR meter?

[Dr Tony Balls]

I'm troubleshooting an effects unit of mine with a built-in transformer (as opposed to being battery-powered). Are there any extra precautions that I need to take, before measuring the electrolytic capacitors with my LCR meter?

PROBABLY not, but what pedal is it?

In a regular solid state pedal you're taking 120 volts AC (240 in the UK/EU) and the transformer will step down the voltage to something more useful to the pedal, say like 12 volts AC. Then the power gets rectified and filtered to something like 9 volts DC and that's what's gonna be on the filter caps and supplying the voltage to the pedal circuit. 12 volts or 9 volts wont hurt you. A Univibe runs at like 18v and event that is just fine.

In contrast, a tube amp takes that 120 volts AC (or 240) and the transformer steps up that voltage to something like 600 volts AC, then rectifies it and filters it to something like 450 volts DC that will be sitting on the filter caps. THAT will fuck you up.

So if you have a pedal that is making low voltage supply, there's less to be concerned about. If you have one that's making high voltage for a tube circuit there's more to be cautious of. Regardless i'd always make sure to keep your fingers away from the mains supply going in to the thing because that can zap you.

[Nick]

Thanks, Balls! That makes sense to me. It's an Arbiter 'Add-a-sound' box, so no tubes or anything.

[underorbit]

Anybody have any idea who made this pickup? For a Stratocaster, measures 5.9, tape seems not original?

https://imgur.com/a/7NiQkxd

[Nick]

Is it ever worth replacing the input/output (and circuit in/out) wiring on a Big Muff style pedal with shielded cable? I'm thinking of messing with my vintage Jumbo Tone Bender to see if I can improve its performance (since it's already been worked on by a previous owner in the past).

[Dr Tony Balls]

Is it ever worth replacing the input/output (and circuit in/out) wiring on a Big Muff style pedal with shielded cable? I'm thinking of messing with my vintage Jumbo Tone Bender to see if I can improve its performance (since it's already been worked on by a previous owner in the past).

Depends who you ask, I suppose. I have never found benefit in shielding the in/out leads inside the box (for a standard pedal, anyway). The stuff you're shielding against (EMI, high current AC) isnt generally coming from a source inside the pedal so the whole thing is shielded by way of its metal box. But it bears mentioning that folks like Dave and Pete Cornish seem to do it quite a lot if not exclusively.

[Nick]

Depends who you ask, I suppose. I have never found benefit in shielding the in/out leads inside the box (for a standard pedal, anyway). The stuff you're shielding against (EMI, high current AC) isnt generally coming from a source inside the pedal so the whole thing is shielded by way of its metal box. But it bears mentioning that folks like Dave and Pete Cornish seem to do it quite a lot if not exclusively.

Yeah, I know those guys have been doing it for years, and I assumed it was a kind of 'good practice' thing to do with high-gain pedals. This pedal could be an interesting opportunity to experiment with that. Quite a lot of companies were using shielded cables for fuzz pedals back in the 60s

[Dr Tony Balls]

Depends who you ask, I suppose. I have never found benefit in shielding the in/out leads inside the box (for a standard pedal, anyway). The stuff you're shielding against (EMI, high current AC) isnt generally coming from a source inside the pedal so the whole thing is shielded by way of its metal box. But it bears mentioning that folks like Dave and Pete Cornish seem to do it quite a lot if not exclusively.

Yeah, I know those guys have been doing it for years, and I assumed it was a kind of 'good practice' thing to do with high-gain pedals. This pedal could be an interesting opportunity to experiment with that. Quite a lot of companies were using shielded cables for fuzz pedals back in the 60s

Right, but looking at the vintage stuff, is a Mk1.5 or Vox Bender any quieter than a Fuzz Face? You could always A/B quickly by just connecting and disconnecting the shield and listening.

[sledz]

If there is any difference in simple layouts, it must be really small. Using it today is more professional-attitude practice or just for the looks, than necessity. It may be obligatory when you route sensitive signals close to 'dirty' circuits like clocks; in fuzz maybe situation when input and output wires need (for space reason) to be routed very close together. Some wires may be microphonic though (usual suspect is teflon, but also I had very good quality PVC wire being microphonic), it's easy to hear with gain cranked and knocking that wire with finger or whatever.